Optical Surface Defect Detection for Round Wire Rods
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Solution Overview
Problem
Existing methods for detecting surface defects in round wire rods, such as ultrasonic, Magnetic Flux Leakage, Magnetic Particle Inspection, eddy current inspection, and optical inspection, face challenges like inefficiency in detecting defects along the transmission direction, instability with temperature changes, difficulty in high-speed applications, and requirement for constant sensor distance, making real-time non-contact detection difficult.
Innovation Solution
A device using a lighting device to emit circular surface light, an optical sensor to receive and convert the reflected light into an image signal, and a signal-processing unit to acquire surface information, along with a speedometer and guides to restrict the wire rod's path, allowing for real-time non-contact detection of defects regardless of diameter changes or vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic flux leakage sensor is used to detect surface defects, then detection sensitivity for cracks is improved, but sensor stability deteriorates under temperature changes
Solution Approach 1:
The patent replaces magnetic field-based detection (MFL) with optical field-based detection. Instead of using magnetic flux leakage sensors that are sensitive to temperature changes, the invention uses optical sensors to detect surface defects through light reflection and scattering properties, thereby eliminating temperature-related stability issues while maintaining detection sensitivity.
Solution Approach 2:
The patent changes the detection parameter from magnetic flux leakage to optical reflection characteristics. By measuring changes in light intensity, scattering patterns, or polarization states rather than magnetic field variations, the system achieves temperature-insensitive defect detection while preserving the ability to detect fine cracks and surface irregularities.
2Productivity
If magnetic flux leakage sensor is used for high-speed detection, then detection speed is improved, but signal accuracy deteriorates due to vibration and distance variation
Solution Approach 1:
The patent substitutes magnetic field-based sensing with optical sensing to achieve high-speed, high-accuracy defect detection. Optical sensors can respond instantaneously to surface defects without the inertia or sensitivity to vibration that plagues magnetic sensors, enabling accurate detection even during high-speed wire rod transport.
Solution Approach 2:
The patent employs periodic scanning or pulsed illumination methods where the optical sensor systematically scans the wire rod surface or uses pulsed light sources with synchronized detection. This periodic action allows the system to maintain high detection speed while averaging out vibration effects and ensuring accurate defect identification through repeated measurements.
3Ease of operation
If optical sensor is used for non-contact detection, then ease of operation is improved, but detection capability deteriorates for defects along transmission direction
Solution Approach 1:
The patent enhances optical detection capability by introducing multiple detection dimensions. Instead of relying on a single optical path, the system uses multiple optical sensors positioned at different angles or locations, or employs multi-directional illumination, thereby enabling detection of defects oriented in various directions including those parallel to the transmission direction while maintaining non-contact operation.
Solution Approach 2:
The patent creates a multi-functional optical detection system that can detect various types of surface defects (cracks, inclusions, roughness, dimensional variations) regardless of their orientation. By combining multiple optical sensing modalities or using sensors with different detection geometries, the system achieves universal defect detection capability while preserving the advantages of non-contact measurement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves accurate detection of defect location, size, and type with improved sensitivity and stability, enabling continuous monitoring without the need for frequent adjustments, even under varying conditions like temperature and speed changes.
Implementation Method 1
an optical sensor for generating an optical signal by receiving light emitted by the lighting device and reflected from the round wire rod
Implementation Method 2
an optical sensor for generating an optical signal by receiving light emitted by the lighting device and reflected from the round wire rod, and converting the optical signal into an image signal
Data Source
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AI summary
A device and method can optically detect a defect of a round wire rod to be tested, and particularly, remotely detect the defect without contact in real-time. The device includes a lighting device for emitting circular surface light to the round wire rod; an optical sensor for generating an optical signal by receiving the light reflected from the round wire rod, which is being transported, and converting the optical signal into an image signal; and a signal-processing unit for acquiring surface information of the round wire rod by receiving the image signal from the optical sensor.